Concerning the structure of a controller of a conventional robot or the structure of a controller similar to it, an upper face portion of a housing of the controller is composed being freely opened and closed by a hinge and further an intermediate partition plate, which is opened and closed by a hinge, is provided in the housing of the controller. Concerning this controller, for example, refer to Patent Document 1. According to Patent Document 1, the following structure is disclosed. For the maintenance of an operating portion or a displaying portion provided inside an upper face portion of a housing, an upper face portion is supported by a hinge being freely opened and closed like a door opened upward. In order to downsize the controller, internal devices of the controller, which are densely arranged in the housing so as to downsize the controller, are partitioned by an intermediate partition plate and when the intermediate partition plate is opened and closed in the longitudinal direction inside the housing like a door, the devices arranged in the inner part of the intermediate partition plate may be checked and maintained.
In a robot controller into which an arc welding electric power source is incorporated, a lower portion of a bulkhead is made to be a portion in which the arc welding electric power source is accommodated and an upper portion of the bulkhead is made to be a portion in which the robot control unit is accommodated. Further, a sliding structure is employed so that the arc welding electric power source may be dragged out. Concerning this structure, for example, refer to Patent Document 2. According to Patent Document 2, the welding electric power source and the robot controller are accommodated in the same housing. Therefore, the entire unit may be downsized and the cables may be orderly laid. Further, when the welding electric power source is slid, the unit may be easily checked and maintained.    Patent Document 1: JP-A-58-181591    Patent Document 2: JP-A-4-365581